1. Field of the Invention
The present invention relates to a meander line antenna that can be used in different frequency bands, the meander line antenna being constituted by a folded conductive pattern.
2. Description of the Related Art
Various flat antennas are proposed for applying to an IC tag (Integrated Circuit Tag), an RF-ID tag (Radio Frequency Identification Tag), and the like, where a meander line antenna is one of the kinds. Various structures of the meander line antenna are proposed, an example being a folded dipole antenna conductive pattern formed in the shape of a zigzag.
An example of a method of manufacturing the meander line antenna that consists of one or more layers of a conductive pattern is known, wherein a meander-like conductive pattern is formed on or in a dielectric substrate and a magnetic substance substrate, the pattern is cut so that a desired antenna property may be acquired, and calcination is performed on the substrate, (for example, Patent Reference 1). Further, according to another known method, a conductive pattern in the shape of a meander serving as a feed radiation electrode, a conductive pattern in the shape of a meander serving as a non-feed radiation electrode, and a conductive pattern for in-series inductance adjustment are formed on a dielectric substrate, wherein the resonance frequency is adjusted by partially removing the conductive pattern for in-series inductance adjustment (for example, Patent Reference 2).
Further, a meander line antenna, a resonance frequency of which is adjustable, is disclosed, wherein the meander line antenna has shorting conductors at two or more places between countering lines of a part of the meander-like conductive pattern. There, the resonance frequency is lowered by selecting cutting points of the shorting conductors; and the resonance frequency is made higher by short-connecting between points of countering lines, such shorting points being properly chosen (for example, Patent Reference 3). Further, a meander antenna that is sealed by dielectrics except for the feeding point of the antenna is known, wherein the resonance frequency is adjusted by selectively removing two or more short circuit sections (for example, Patent Reference 4).
Further, characteristics measurements and simulations are conducted about a meander line antenna applicable to IC tags, and the like, wherein the length of the meander line antenna is set between 0.025 and 0.1 wavelength at 700 MHz, and parameters are width W, length L, line width d, line pitch s, the number of folding times N, and the like of the target antenna (for example, Non-Patent Reference 1).
[Patent Reference 1] JPA 2001-119224
[Patent Reference 2] JPA 2001-217631
[Patent Reference 3] JPA 2002-330018
[Patent Reference 4] JPA 2004-32102
[Non-Patent Reference 1] “Radiation and Ohmic Resistances in Very Small Meander Line Antennas of Less than 0.1 Wavelength”, Masato Takiguchi and Yoshihide Yamada, The Institute of Electronics, Information and Communication Engineers, IEICE Transaction B, Vol. J87-B No. 9, pp 1336–1345, September 2004.